Contemporary Physics
Antimatter
P. Thornton Greenland
Abstract
Antihydrogen has recently been produced in CERN. I discuss the original motivation for the study of antimatter, and describe the large, but as yet unsuccessful attempt to produce cold antihydrogen confined to a trap, where it can be studied spectroscopically, and compared with ordinary hydrogen. I also describe the experiment at CERN, which produced ∼ 11 atoms of antihydrogen moving at 90% of the speed of light, circumstances that make precision spectroscopy difficult.